Law enforcement sources on the condition of anonymity said that the authorities found an image of a potential suspect but were yet to identify the person. The development took place in less than 48 hours after the attack, which had rocked an age-old marathon carnival in the heart of the city, marked a possible turn around in the case.
The sleuths found the image on a surveillance footage received from the store located near the finishing line and matched the findings with witnesses' version of someone leaving the scene after dropping a bag.
The explosives used in Tuesday's blasts were crudely fashioned from ordinary kitchen pressure cookers packed with nails and ball bearings, investigative sources said.
There was, however, some contradictory reports in the middle of the development. A law enforcement official said a suspect was in custody and was expected to appear in the federal court while the FBI and the US attorney's office here said no arrests had taken place.
Meanwhile Boston remained under a tight security and the local people said they were still feeling nervous to come out of their house and move around. At least 14 victims of the bombing still remained in critical condition.